Instrumental conditioning and learning in Poroderma Pantherinum

Recent research has shown that higher cognitive functions and learning occur in teleosts and elasmobranchs. Very little is known about the cognitive abilities of benthic sharks and no research has been published on the learning ability of the endemic Leopard catshark (Poroderma pantherinum) species of South Africa. This species is listed as data deficient on the IUCN red list and known threats due to anthropogenic impacts include fatalities because of bycatch and depredation in the small-scale commercial fishing industry. It has been suggested that sharks can be attracted to fishing boats through the sound of outboard motors and an association can be formed between the sound and easy prey on the hooks of fisherman. This pilot study examined the learning capacity of Leopard catsharks in Hermanus, South Africa, by using a series of food-reward tests based on instrumental conditioning. A target with black and white stripes was used as the discriminative stimulus, while an auditory cue acted as a bridging stimulus for the food-reward task. Sharks were collected by hand whilst diving and shore-angling in Hermanus from August 2015 to November 2015 and acclimatised before the onset of experiments. Four juvenile sharks were trained through operant conditioning using visual and auditory stimuli for ten days each, consisting of six trials per day. A fifth juvenile shark, acting as the control, was trained through the same method without the auditory stimulus to test the influence thereof on the learning rates of Leopard catsharks. This study showed that Leopard catsharks have the ability to associate a visual stimulus with a food reward through the aid of an auditory cue. The auditory cue was also shown to increase learning rates significantly as an association was formed between the presence of food in front of the target and the auditory signal. The individual sharks in this study displayed differing levels of stress and learning rates. It is suggested that even though Leopard catsharks show high diversity in learning rates and adaptation to stress, they possess the ability to learn and adapt rapidly to changing environments. The results possibly have important implications for the understanding of learning and conditioning in Leopard catsharks and the likely anthropogenic threats caused through learned behaviour in benthic sharks.